1. Field of the Invention
The present invention generally relates to a disc player and, more particularly, to a pickup feeding apparatus for feeding an optical pickup head.
2. Description of the Prior Art
Recently, a portable small disc player has been widely used as a disc player, particularly, a compact disc player. A pickup feeding mechanism portion of such conventional portable small disc player is arranged as shown in a plan view forming FIG. 1.
Referring to FIG. 1, a pickup head 41 is provided to read out a recorded signal from a disc (not shown), and this pickup head 41 is supported to a guide shaft 42 secured to a mechanical chassis (not shown) so as to move along the guide shaft 42 in the radius direction of the disc as shown by an arrow A in FIG. 1.
The pickup head 41 is provided with a rack 43 at its side opposite to the guide shaft 42. The rack 43 is meshed with an operation gear 44 that is rotated by a pickup moving motor (not shown). When the operation gear 44 is rotated by the motor, a rotational force of the operation gear 44 is transmitted to the rack 43 to thereby feed the pickup head 41.
In the thus arranged pickup feeding apparatus, if a backlash (play between teeth) lies between the rack 43 and the operation gear 44, a sufficient pickup servo characteristic cannot be obtained. Therefore, the rack 43 is constructed as a so-called double rack structure in order to prevent the vibration from being caused due to the backlash. This double rack structure will be explained below with reference to FIG. 2.
As shown in FIG. 2, the rack 43 is composed of a first rack 43a secured to the pickup head 41 and a second rack 43b slidable relative to the first rack 43a in the direction parallel to the pickup head moving direction. The second rack 43b is spring-biased in one direction by a spring member (compression coil spring) 45 so that teeth of the operation gear 44 are caught by the teeth of the two racks 43a and 43b, thereby removing the backlash.
As described above, in the pickup feeding apparatus of the standard disc player, the rack must be constructed as the double rack structure in order to remove backlash occurring between the rack and the operation gear, and the spring member must be provided in order to spring-bias one rack, which requires a spacing of this spring member. This hinders the pickup feeding apparatus from being miniaturized.
Incidentally, a drive mechanism of a disc player is generally comprised of a disc drive mechanism for rotating a disc and a pickup feeding mechanism for feeding a pickup device which reads out a signal from the disc.
These disc drive mechanism and pickup feeding mechanism include motors and drive circuits for controlling these motors, respectively.
Considering the arrangement in which the motors and the drive circuits are provided in the disc player, the motors and the drive circuits are independently mounted on the disc player. To be more concrete, the motor finished as one motor unit is attached to the mechanical chassis and the driving circuit for this motor is mounted on a circuit board which is attached to the mechanical chassis at its portion different from that of the motor.
As earlier stated, the portable thin-type disc player has become very popular recently and it is requested that the disc player be made compact in size and be reduced in thickness much more. However, since the motor and the circuit board are independently provided in the conventional disc player as described above, unavoidably the disc player cannot be miniaturized in size and reduced in thickness as is expected.